複数行入力 - Haskell-Misc

複数行入力

簡単な行編集可能

REPLを構成しやすいようにLazy I/O

code:InputLines.hs

-- # InputLines.hs

-- ## 言語拡張とmodule宣言

{-# LANGUAGE GHC2021 #-}

{-# LANGUAGE ImplicitParams #-}

{-# LANGUAGE ImportQualifiedPost #-}

{-# LANGUAGE LexicalNegation #-}

{-# LANGUAGE LambdaCase, MultiWayIf #-}

{-# LANGUAGE NPlusKPatterns #-}

{-# LANGUAGE DataKinds, PolyKinds, NoStarIsType, TypeFamilyDependencies #-}

{-# LANGUAGE OverloadedStrings #-}

{-# LANGUAGE OverloadedRecordDot, NoFieldSelectors, DuplicateRecordFields #-}

module InputLines

( inputLines

, ginputLines

) where

import Data.Bool

import Data.Char

import Data.List

import System.Console.Haskeline

import System.IO.Unsafe

inputLines :: String

-> String

-> IO String

inputLines prompt quit = ginputLines prompt quit '\n'

inputLines :: String

-> String

ginputLines :: String -- ^ prompt

-> String -- ^ quit comand

-> Char -- ^ terminator

-> IO String

ginputLines p q t = loop id where

loop :: (String -> String) -> IO String

loop acc = unsafeInterleaveIO $ do

{ minput <- runInputT defaultSettings (getInputLine p)

; case minput of

Nothing -> return []

Just input

| input == q -> return []

| otherwise -> case break (t ==) input' of

(_,[]) -> loop (acc' . (input' ++))

(str,_) -> (acc' str :) <$> loop id

_ -> error "invalid input"

where

input' = trim input

acc' = bool (acc . (' ' :)) id (acc "" == "")

}

trim :: String -> String

trim = dropWhileEnd isSpace . dropWhile isSpace